There exists an everlasting problem within pharmacy to be able to administer a therapeutically active compound as close as possible to the colon, or preferably in the colon in order to thereby to eliminate the risk for acidic influence on the active compound by the gastric juice, or to prevent from irritation of the ventricular mucous membrane due to a reflux, or to obtain a therapeutical effect in the lower part of the gastrointestinal tract.
As suitable active compounds it has previously been proposed propanolol, alprenolol, and metoprolol tartrate, quinidine sulphate, quinidine bisulphate, quinidine hydrochloride, furosemide, and 5aminosalicylic acid, i.e., such weak bases or salts thereof, the pH of which is 1 to 8.